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DPhil Projects Available

We are always looking for talented students who want to study for a PhD (DPhil) in our group. Follow the links below for more information.

If you are interested in doing a DPhil (PhD) in Professor Warner's group, then you must formally apply to the Department of Materials, University of Oxford. If you list one of the projects offered by Professor Warner in your application, then your application will be sent to him for further assessment.

Projects:

1. Synthesis of large area graphene sheets using chemical vapour deposition for electronic applications

Supervisor: Professor Jamie Warner

The 2D crystalline nature of graphene makes it suitable for large area transparent conducting electrodes and in nanoelectronics. The biggest challenge in synthetic graphene is achieving large single crystals of graphene and uniformity in the layer number on the centimeter scale. We have recently shown how chemical vapour deposition (CVD) can be used to grow centimeter scale continuous films of pure monolayer graphene with graphene crystal grain sizes approaching the millimeter scale. This project will extend this body of work to focus on understanding the growth mechanisms behind CVD grown graphene and then developing approaches to improve the atomic structure and electronic properties. Techniques to transfer the sheets to transparent substrates, such as glass or flexible polymers will be examined and the sheet resistance determined. Nanoelectronic devices such as field effect transistors and Hall bar structures will be fabricated using lithography in order to evaluate the electronic properties of the synthetic graphene. Methods to incorporate dopants into the CVD growth process will be pursued with the aim of improving conductivity. Controlling the number of graphene layers grown by CVD will be investigated. The material produced in this project will underpin a wide range of applications based on graphene and has the potential for significant impact.

2. Sensor Technology Based on Large Area Synthetic Graphene

Supervisor: Professor Jamie Warner

Sensor technology, such as touch screen displays and pressure/strain sensors, will be developed using graphene. The graphene will be synthetic and of large area, produced using metal catalyst assisted chemical vapour deposition. Processing methods for transferring the graphene onto transparent flexible polymer substrates will be developed. This project aims at bringing graphene into application and will utilize recent advances within the group for producing outstanding synthetic graphene material. Optical and electron beam lithography will be used to pattern the graphene and metal electrodes for devices. Interfacing with computer hardware will be undertaken to achieve functioning sensor technology.

3. Structural studies of Graphene and other 2D crystals with single atom sensitivity

Supervisors: Professor Jamie Warner and Professor Angus Kirkland

Graphene is a 2D crystal only one atom thick and is ideal for studying individual carbon atoms using transmission electron microscopy. This project will focus on understanding fundamental crystal defects in graphene, such as edge dislocations (both glide and shuffle), mono-vacancies and the other non-6 member ring structures that exist in the unique 2D crystal. It will also investigate the grain boundary interface between two graphene domains with the aim of mapping out the unique atomic stitching that occurs. Graphene will be grown by chemical vapour deposition. This project will use Oxford's state-of-the-art aberration-corrected high resolution transmission electron microscope, equipped with a monochromator for the electron beam to give unprecedent spatial resolution at a low accelerating voltage of 80 kV. Advanced image analysis techniques, such as exit-wave reconstruction, and comparison to image simulations will be utilized for a deeper understanding of the atomic structure.

Supervisor: Professor Jamie Warner

Graphene is a semi-metal 2D crystal, Boron Nitride (BN) an insulating 2D crystal, and MoS2/WS2 are semiconducting 2D crystals. Realizing the potential of 2D crystals in electronic applications requires all 3 of these variants. We have undertaken years of research in growing graphene crystals by chemical vapour deposition and can now produce high quality materials. However, further improvement is needed to advance the synthesis of BN and MoS2/WS2 2D crystals to obtain similar quality films. In this project 2D crystals will be synthesized by chemical vapour deposition to produce materials with varying band structure. New synthetic strategies will be developed in order to produce large single crystal structures on a variety of substrates compatible with device processing.

The atomic structure of the new 2D crystals will be characterized using advanced electron microscopy (scanning electron microscopy and transmission electron microscopy). The electronic properties of the new materials will be analysed by fabricating nanoelectronic devices such as transistors. This is a unique opportunity to undertake a project involving new materials synthesis, characterization of the atomic structure, and implementation in nanoelectronic transistor arrays. The project is well integrated into the group's goals by developing new 2D crystals that will have large up-take amongst other researchers for a applications ranging from flexible electronics, pressure sensors, optical detectors, LEDs and solar cells.

5. Graphene electrodes for Energy Devices

Supervisor: Professor Jamie Warner

Graphene is an ideal 2D material for utilization as a transparent conducting electrode in photovoltaics (solar cells). High efficiency photovoltaic devices will require the effective integration of other nanomaterials with graphene to produce hybrid nanosystems. Inorganic nanocrystals such as PbS, ZnSe, TiO2 and Si, have unique semiconducting properties with band gaps that span from the near-IR to UV. This project will focus on synthesizing inorganic nanocrystals using solution-phase chemistry. Control over the shape to tailor spherical, rod and branched structures will be investigated. Variation of surface state morphology will be conducted through various chemical approachs to control the inter-nanocrystal interactions. Synthetic graphene will be produced using chemical vapour deposition. Composite hybrid devices will be fabricated that use synthetic graphene as a working transparent conducting electrode and the inorganic nanocrystal as the active functional nanomaterial.